Parsing the UK Postcode

import re

pattern = r'^(((([A-Z]{1,2})[0-9])[A-Z])|(([A-Z])[0-9])|(([A-Z]{1,2})[0-9]{1,2})) ([0-9]([A-Z]{2}))$'

def parse(post_code):
    # parses the given postcode returning a dict with the fields
    match = re.match(pattern, post_code)

    if match is not None:
        # the regex tries to distinguish between different configurations
        # the presence of group 2 or 5 is used to separate the three cases
        if(match.group(2) is not None):
            return {
                'Valid': True,
                'Otutward Code': match.group(1),
                'Inward Code': match.group(9),
                'Postcode Area': match.group(4),
                'District Code': match.group(3),
                'Sub Discrict': match.group(1),
                'Unit': match.group(10)
            }
        elif(match.group(5) is not None):
            return {
                'Valid': True,
                'Otutward Code': match.group(1),
                'Inward Code': match.group(9),
                'Postcode Area': match.group(6),
                'District Code': match.group(5),
                'Sub Discrict': None,
                'Unit': match.group(10)
            }
        else:
            return {
                'Valid': True,
                'Otutward Code': match.group(1),
                'Inward Code': match.group(9),
                'Postcode Area': match.group(8),
                'District Code': match.group(7),
                'Sub Discrict': None,
                'Unit': match.group(10)
            }
    else:
        # the string is not a valid postcode
        return { 'Valid': False}

def test(parsed, outward, inward, area, district, sub, unit):
    # compares the dict with the expected values
    if(parsed['Otutward Code'] != outward):
        raise Exception('error')
    if(parsed['Inward Code'] != inward):
        raise Exception('error')
    if(parsed['Postcode Area'] != area):
        raise Exception('error')
    if(parsed['District Code'] != district):
        raise Exception('error')
    if(parsed['Sub Discrict'] != sub):
        raise Exception('error')
    if(parsed['Unit'] != unit):
        raise Exception('error')

# values tested with https://ideal-postcodes.co.uk/guides/uk-postcode-format

# this covers all cases
# the postcode (first parameter) is split in the other parameters

test(parse('AB1C 2DE'), 'AB1C', '2DE', 'AB', 'AB1', 'AB1C', 'DE')
test(parse('B1C 2DE'), 'B1C', '2DE', 'B', 'B1', 'B1C', 'DE')
test(parse('B1 2DE'), 'B1', '2DE', 'B', 'B1', None, 'DE')
test(parse('B12 3DE'), 'B12', '3DE', 'B', 'B12', None, 'DE')
test(parse('AB1 2CD'), 'AB1', '2CD', 'AB', 'AB1', None, 'CD')
test(parse('AB12 3CD'), 'AB12', '3CD', 'AB', 'AB12', None, 'CD')

# some extra tests with the provided examples

test(parse('M1 1AA'), 'M1', '1AA', 'M', 'M1', None, 'AA')
test(parse('M60 1NW'), 'M60', '1NW', 'M', 'M60', None, 'NW')
test(parse('CR2 6XH'), 'CR2', '6XH', 'CR', 'CR2', None, 'XH')
test(parse('DN55 1PT'), 'DN55', '1PT', 'DN', 'DN55', None, 'PT')
test(parse('W1A 1HQ'), 'W1A', '1HQ', 'W', 'W1', 'W1A', 'HQ')
test(parse('EC1A 1BB'), 'EC1A', '1BB', 'EC', 'EC1', 'EC1A', 'BB')